Upon 1st starting the car as I reach 10mph I hear 5 pops from front driver wheel area.After that reverse,drive,park,back to drive it will not pop again.Cut the car off and let it power down(30seconds)and at 10mph it pops again.i believe it's rear wheel drive TIL 8 mph when the actuator motor engaged the front wheel drive part .Once the allwheel is fully engaged it stays in allwheel TIL powered down.Any info on this would be greatly appreciated